CENTRAL ISLIP, N.Y. -- A medical biller has been sentenced to 12 years in federal prison after being convicted in a massive insurance fraud scheme that involved posing as NBA player Marcus Smart, an NFL lawyer and executive, and other patients to harangue the companies for payments that weren't actually due, prosecutors said.

U.S. District Judge Joanna Seybert called Matthew James' actions "inexcusable" as she sentenced him Friday in Central Islip, Newsday reported.

"To ruin people's reputations, to do all that, for wealth is really something," Seybert said.

James, 54, was convicted in July 2022 of fraud and identity theft charges. Prosecutors say he bilked insurance companies out of hundreds of millions of dollars.

James ran medical billing companies. Prosecutors said he got some doctors to schedule elective surgeries via emergency rooms -- a tactic that boosted insurance reimbursement rates -- and billed for procedures that were different from the ones actually performed. When insurance companies rejected the claims, he called, pretending to be an outraged patient or policyholder who was facing a huge bill and demanding that the insurer pay up.

One person he impersonated was Smart, who underwent hand surgery after hitting a picture frame in 2018, according to court papers filed by James' lawyers.

Smart was then with the Boston Celtics, and in 2022 was the first guard to win the NBA Defensive Player of the Year award in more than a quarter-century. Smart now plays for the Memphis Grizzlies.

Smart testified at James' trial that the impersonation upset him because he wasn't raised to treat people the way James did and that he was concerned it would damage his standing as a role model, according to prosecutors' court papers.

Another victim was NFL lawyer and executive Jeff Pash, whose wife was treated for an injury she got while running in 2018. Jurors at James' trial heard a recording of someone who purported to be Pash -- but actually was James -- hollering and swearing at a customer service representative on an insurance provider's dedicated line for NFL employees, Newsday reported at the time.

"These are people that work for the NFL, and I would hate to have them think that was me on that call," Pash testified, saying he knew nothing about it until federal agents told him.

James' lawyer, Paul Krieger, said in a court filing that James worked as a nurse before starting his own business in 2007. James developed a drinking problem in recent years as he came under stress from his work and family responsibilities, including caring for his parents, the lawyer wrote.

"He sincerely and deeply regrets his misguided phone calls and communications with insurance companies in which he pretended to be patients in an effort to maximize and expedite payments for the genuine medical services provided by his doctor-clients," the attorney added, saying the calls were "an aberration" in the life of "a caring and decent person."